All things related to multicast

["Sergey Velikanov [Intelsoft]" <>]

Hello

I've connected second MSDP peer, but all SA from this peer has rejected 
becouse rpf check fail, but I can't understand why it happer

My topology is


|ISP1                   |    optical link     |ISP2     
|                       |                     |
| * RP (172.16.0.2)     |                     |         * RP (17.15.78.130)
|                  172.16.224.2 <======> 172.16.224.1
|                       |                     |
|                       |                     |

we establish msdp session beetween 172.16.224.2 and 17.15.78.130

my config is

ip msdp peer 172.16.224.2 connect-source Loopback1 remote-as 25
ip msdp description 172.16.224.2 RP on Digital TV
ip msdp originator-id Loopback1
ip msdp rpf rfc3618

interface Loopback1
 description User for Anycast and MSDP peers
 ip address 17.15.78.130 255.255.255.255
end


debug ip msdp peer
%MSDP-5-PEER_UPDOWN: Session to peer 172.16.224.2 going up
49w2d: MSDP(0): 172.16.224.2: TCP connection established
49w2d: MSDP(0): 172.16.224.2: Received 3-byte msg 467 from peer
49w2d: MSDP(0): 172.16.224.2: Keepalive TLV
49w2d: MSDP(0): 172.16.224.2: Sending Keepalive message to peer
49w2d: MSDP(0): 172.16.224.2: Received 1400-byte msg 468 from peer
49w2d: MSDP(0): 172.16.224.2: SA TLV, len: 1400, ec: 116, RP: 172.16.0.2
49w2d: MSDP(0): 172.16.224.2: RPF check failed for 172.16.0.2
49w2d: MSDP(0): 172.16.224.2: Received 272-byte msg 469 from peer
49w2d: MSDP(0): 172.16.224.2: SA TLV, len: 272, ec: 22, RP: 172.16.0.2
49w2d: MSDP(0): 172.16.224.2: RPF check failed for 172.16.0.2
49w2d: MSDP(0): 172.16.224.2: Originating SA message, originator-id 
17.15.78.130
49w2d: MSDP(0): 172.16.224.2: Sending Keepalive message to peer
49w2d: MSDP(0): 172.16.224.2: Building SA message from SA cache

r2office#sh ip msdp sa-cache rejected-SA d read-only
MSDP Rejected SA Cache
521 rejected SAs received over 00:40:40, cache size: 100 entries
Timestamp (source, group)
29814901.249, (10.0.0.6, 224.1.1.5), RP: 172.16.0.2, Peer: 172.16.224.2, 
Reason: rpf-fail
29814901.249, (10.0.0.6, 224.1.1.4), RP: 172.16.0.2, Peer: 172.16.224.2, 
Reason: rpf-fail
29814901.249, (10.0.0.6, 224.1.1.7), RP: 172.16.0.2, Peer: 172.16.224.2, 
Reason: rpf-fail
29814901.249, (10.0.0.6, 224.1.1.6), RP: 172.16.0.2, Peer: 172.16.224.2, 
Reason: rpf-fail
29814901.249, (10.0.0.6, 224.1.1.9), RP: 172.16.0.2, Peer: 172.16.224.2, 
Reason: rpf-fail


why it fail inspite of that route to RP exist in routing table

office#sh ip msdp rpf-peer 172.16.224.2
RPF peer information for Digital.TV.RP (172.16.224.2)
  RPF peer: Digital.TV.RP (172.16.224.2)
  RPF route/mask: 172.16.224.0/30
  RPF rule: Peer is RP
  RPF type: unicast (ospf 1)

office#sh ip msdp rpf-peer 172.16.0.2
RPF peer information for ? (172.16.0.2)
RPF peer does not exist

office#sh ip rpf 172.16.224.2
RPF information for Digital.TV.RP (172.16.224.2)
  RPF interface: Vlan999
  RPF neighbor:  17.15.76.139
  RPF route/mask: 172.16.224.0/30
  RPF type: unicast (ospf 1)
  RPF recursion count: 0
  Doing distance-preferred lookups across tables

office#sh ip rpf 172.16.0.2
RPF information for ? (172.16.0.2)
  RPF interface: Vlan999
  RPF neighbor: 17.15.76.139
  RPF route/mask: 172.16.0.2/32
  RPF type: unicast (ospf 1)
  RPF recursion count: 0
  Doing distance-preferred lookups across tables